Australia has an enviable, strong economy with a per capita GDP on par with the four dominant West European economies. Robust business and consumer confidence and high export prices for raw materials and agricultural products are fueling the economy, particularly in mining states. Australia's emphasis on reforms, low inflation, a housing market boom, and growing ties with China have been key factors behind the economy's 16 solid years of expansion. Drought, robust import demand, and a strong currency have pushed the trade deficit up in recent years, while infrastructure bottlenecks and a tight labor market are constraining growth in export volumes and stoking inflation. Australia's budget has been in surplus since 2002 due to strong revenue growth.